# API model extension

* adds model ExternalIdentifier to support linking between external ids and internal ids

api/models/__init__.py

@@ -5,4 +5,5 @@ Contact: michel.peltriaux@sgdnord.rlp.de
 Created on: 21.01.22
 
 """
-from .token import *
+from .token import *
+from .external_identifier import *

api/models/external_identifier.py

@@ -0,0 +1,33 @@
+"""
+Author: Michel Peltriaux
+Created on: 10.05.26
+
+"""
+from django.db import models
+
+
+class ExternalIdentifier(models.Model):
+    """ Holds a lookup to match a given external identifier against the internal identifier in konova.
+
+    Relevant in cases of API transmitted entries, which are updates using external identifiers instead of
+    the internal ones directly.
+
+    """
+    external_id = models.CharField(
+        max_length=255,
+        primary_key=True,
+        db_comment="Identifier from a source system"
+    )
+    internal_id = models.UUIDField(
+        db_comment="Identifier in konova"
+    )
+    created = models.ForeignKey(
+        "user.UserActionLogEntry",
+        on_delete=models.SET_NULL,
+        null=True,
+        blank=True,
+        related_name='+'
+    )
+
+    def __str__(self):
+        return f"{self.external_id} -> {self.internal_id}"